液相色谱-串联质谱法测定人血浆中儿茶酚胺的含量

建立人血浆中儿茶酚胺液相色谱-串联质谱(LC-MS/MS)的检测方法。采用Agilent Zorbax Eclipse XDB-C18(4.6 mm×150 mm,5μm)柱子,柱温25℃,流动相为V(乙腈)∶V(0.1%甲酸溶液)=10∶90,流速0.6 mL/min,进样量20μL;电喷雾离子源(ESI),正离子检测,采用多反应监测(MRM)方式进行定量分析。肾上腺素、去甲肾上腺素和多巴胺的最小检测限(LOD)在4.3,2.4和6.6ng/mL之间,浓度在0~500 ng/mL范围内线性良好(r=0.9921),平均回收率在85.8%~93.4%之间,日内、日间精密度RSD为9%(n=5)。结果表明该方法专属性强、灵敏及准确,可以适用于人血浆儿茶酚胺的快速分析。     

液相色谱-串联质谱法测定水产品中亮绿、亚甲基蓝及其代谢物残留量

建立了水产品中亮绿、亚甲基蓝及其代谢物残留量同时测定的液相色谱-串联质谱(LC-MS/MS)方法。样品经乙酸铵缓冲溶液和乙腈提取,二氯甲烷液液萃取,PRS固相萃取柱净化,氮吹浓缩,定容后测定。以2 mmol/L乙酸铵(含0. 1%甲酸)、乙腈和甲醇为流动相,CAPCELL PAK C_(18)色谱柱进行分离,在选择反应监测(SRM)模式下测定,外标法定量。在最佳实验条件下,5种化合物在1. 0～100. 0μg/L范围内线性关系良好(r~2 0. 999),检出限(LOD,S/N≥3)均为1. 0μg/kg,定量下限(LOQ,S/N≥10)均为2. 0μg/kg;在水产品中加标水平为1. 0、5. 0、10. 0μg/kg时,回收率为70. 3%～92. 1%,相对标准偏差(RSD,n=6)为2. 3%～13%。该方法灵敏度高,能有效检测水产品中亮绿、亚甲基蓝及其代谢物的残留量。     

同位素稀释高效液相色谱-串联质谱法测定水体、底泥、鱼及虾中氯硝柳胺残留量

建立了水体、底泥、鱼体自然比例带皮肌肉和虾肌肉中氯硝柳胺(NIC)残留量测定的同位素稀释高效液相色谱-串联质谱(HPLC-MS/MS)法。水样经碱化后以乙酸乙酯提取,其他样品采用0.1%氨水乙腈提取,C_(18)粉进行样品净化。以乙腈-水为流动相,流速为0.3 mL/min,采用Thermo Hypersil Gold C_(18)(150 mm×2.1 mm,5μm)色谱柱进行分离,氯硝柳胺稳定同位素标记物(氯硝柳胺-~(13)C_6)为内标,选择反应监测(SRM)模式扫描,内标法定量。结果表明氯硝柳胺在0.2～200μg/L范围内呈良好线性关系,相关系数(r~2)不小于0.999 5。空白水样在2.5、25、250 ng/L加标水平下的平均回收率为90.5%～109%,相对标准偏差(RSD)为3.2%～11%,检出限(LOD)为1.0 ng/L,定量下限(LOQ)为2.5 ng/L;空白底泥、黄颡鱼自然比例带皮肌肉和克氏原螯虾肌肉在0.5、5.0、50μg/kg加标水平下的平均回收率分别为89.4%～113%、92.8%～110%和94.1%～107%,RSD分别为4.6%～12%、2.8%～11%和3.2%～9.3%,LOD均为0.2μg/kg,LOQ均为0.5μg/kg。该方法的灵敏度、准确度和选择性高,适用于实际水产养殖环境水体、底泥、鱼和虾中氯硝柳胺的残留分析。     

超高效液相色谱-串联质谱法同时测定化妆品中35种性激素

采用超高效液相色谱-串联质谱(UPLC-MS/MS)建立了同时测定化妆品中35种性激素的方法。样品经50%乙腈水溶液超声提取,采用CORTECS C_(18)(2.1 mm×150 mm,2.7μm)色谱柱分离,以乙腈-水为流动相进行梯度洗脱,多反应监测(MRM)模式测定。结果表明,35种性激素在各自的质量浓度范围内线性关系良好(相关系数r0.99),检出限(LOD)和定量下限(LOQ)分别为0.028～0.117μg/g和0.093～0.352μg/g。在0.25、0.50、1.00μg/g 3个加标水平下,水状、乳状和霜状3种基质样品的回收率为84.0%～117%,相对标准偏差(RSD,n=6)为1.5%～14%。该方法前处理简单、灵敏度高、准确性好,适用于化妆品中性激素的测定。     

气相色谱-质谱法测定药用丁基橡胶塞中18种多环芳烃的含量

建立了气相色谱-质谱(GC-MS)联用技术测定药用丁基橡胶塞中18种多环芳烃(PAHs)。用正己烷-丙酮(体积比1∶1)对样品进行超声极限浸提,浸提液经固相萃取柱净化后,用DB-EUPAH柱(60 m×0.25 mm×0.25μm)分离,质谱以选择离子监测(SIM)模式检测,内标法定量。对浸提溶剂、浸提比例和极限浸提进行考察后,在优化条件下,PAHs的峰面积与质量浓度在低浓度范围1～10 ng/mL和高浓度范围10～200 ng/mL均呈现良好的线性关系,线性相关系数r均大于0.9992。方法检出限(LOD)为0.2～10 ng/g,定量限(LOQ)为1～10 ng/g。在1、10和100 ng/g加标水平下的平均回收率为76.63%～113.93%,相对标准偏差(RSD,n=3)为0.11%～6.86%。该方法灵敏度高、准确性好,适用于药用丁基橡胶塞中18种PAHs含量的同时测定。     

高效液相色谱法测定富含油脂辣椒制品中的辣椒素类物质

建立了高效液相色谱法测定高油脂辣椒制品中3种主要辣味成分的方法.样品以70%乙醇提取,采用反相高效液相色谱分离,紫外检测器;根据色谱峰的保留时间定性,以外标峰面积法定量辣椒素(C)、二氢辣椒素(DC)、去甲二氢辣椒素(NDC),结果以斯氏指数(SHU)计.NDC的色谱行为与C极其类似,NDC可采用C的标准曲线定量.采用色谱柱,ZORBAX SB-C18;流动相,V(甲醇)∶V(水)=70∶30;UV检测波长,230 nm;辣椒素和二氢辣椒素RSD分别为1%,1.5%(n=5);回收率分别为97.5%、94.5%.辣椒素和二氢辣椒素在0.001～0.1 mg/mL范围内线性良好;LOD 0.1 mg/L,LOQ 0.5 mg/L.供试品溶液稳定,12 h内测定RSD为1%.方法满足辣味水平评价要求.     

气相色谱-串联质谱动态多反应监测模式测定陈皮中88种农药残留

该文采用改进的QuEChERS结合气相色谱-串联质谱(GC-MS/MS)建立了陈皮中88种农药残留在动态多反应检测(dMRM)模式下的检测方法。对样品提取方式进行筛选优化,采用乙腈为提取剂,加入无水硫酸镁4.0 g、无水乙酸钠1.0 g、陶瓷均质子提取,以PSA 200 mg、C_(18)100 mg、GCB 30 mg净化,通过基质匹配外标法校正,减弱了陈皮中基质效应对目标化合物定量准确性的影响。结果表明,88种农药在一定浓度范围内的线性关系良好,相关系数(r~2)均不低于0.996 3,以3倍信噪比(S/N=3)计算得方法检出限(LOD)为0.001 0～0.050 0 mg/kg,以S/N=10计算得定量下限(LOQ)为0.002～0.100 0 mg/kg;在低、中、高3个加标浓度下的平均回收率为60.1%～118%,相对标准偏差(RSD)为0.30%～13%(n=6)。方法快速高效、灵敏可靠,适用于陈皮中农药残留的快速筛查及日常检测。     

QuEChERS/超高效液相色谱-串联质谱法同时测定水产品中四溴双酚A与六溴环十二烷

建立了同时测定水产品中四溴双酚A(TBBPA)和六溴环十二烷(HBCD)的超高效液相色谱-串联质谱方法。样品前处理采用QuEChERS方法,均质生物样品用水分散后加乙腈提取,经C_(18)分散固相萃取净化。采用CORTECS~?C_(18)色谱柱(4.6 mm×100 mm×2.7μm)分离,以甲醇-水为流动相进行梯度洗脱,流速为0.7 mL/min。采用电喷雾离子源,在负离子模式下以多反应监测(MRM)方式检测。结果表明,TBBPA和3种HBCD单体在0.5～500μg/L范围内线性良好,相关系数(r)大于0.998,检出限(LOD,S/N=3)和定量下限(LOQ,S/N=10)分别为0.04～0.16μg/kg和0.12～0.55μg/kg。在5、20、50μg/kg加标水平下的平均回收率为74.0%～121%,相对标准偏差(RSD)为0.20%～23%。该方法操作简单、快速、重现性好,适用于水产品中TBBPA和HBCD的快速检测。     

稳定同位素直接稀释/超高效液相色谱-串联质谱法测定葡萄酒中赭曲霉毒素A

建立了稳定同位素直接稀释/超高效液相色谱-串联质谱(UPLC-MS/MS)测定葡萄酒中赭曲霉毒素A(OTA)的方法。葡萄酒样品经乙腈-水-甲酸(29.8∶70∶0.2,体积比)溶液稀释后,加入稳定同位素消除基质效应的影响。采用ACQUITY BEH C_(18)色谱柱(100 mm×2.1 mm,1.7μm)分离,以0.1%甲酸水-0.1%甲酸乙腈为流动相梯度洗脱,以电喷雾离子源正离子模式(ESI~+)扫描,多反应监测(MRM)模式采集,内标法定量。结果表明,OTA在0.05～1μg/L范围内线性关系良好,相关系数(r~2)为0.999 6,检出限(LOD,S/N≥3)为0.1μg/L,定量下限(LOQ,S/N≥10)为0.3μg/L。在1.00、2.00、5.00μg/L加标水平下,回收率为102%～113%,日内相对标准偏差(RSD)为4.1%～9.4%,日间RSD为4.4%～9.7%。利用该方法对国产品牌的15种红葡萄酒和5种白葡萄酒进行测定,均未检出OTA。此方法简单、高效、节约成本,可用于大批量葡萄酒中OTA的快速、准确检测。     

高效液相色谱法测定阿达帕林含量

建立了高效液相色谱法测定阿达帕林的含量。以Kromasil C_(18)(250 mm×4.6 mm,5μm)为色谱柱,检测波长为234 nm,以甲醇–四氢呋喃–三氟乙酸–水(450∶25∶0.4∶24.6)为流动相,流量为1.0 mL/min,进样体积为10μL。阿达帕林的质量浓度在2.51～200.8μg/mL范围内与色谱峰面积呈良好的线性关系,相关系数为0.999 9,方法检出限为0.120 8μg/mL。样品加标回收率为99.04%～100.20%,测定结果的相对标准偏差为0.12%～0.24%(n=6)。该方法简便,测定结果准确、可靠,耐用性较强,适用于阿达帕林含量的测定。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.